EP0381878A1 - Verfahren und Gerät zur Diagnose von Netzwerken - Google Patents

Verfahren und Gerät zur Diagnose von Netzwerken Download PDF

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Publication number
EP0381878A1
EP0381878A1 EP89301198A EP89301198A EP0381878A1 EP 0381878 A1 EP0381878 A1 EP 0381878A1 EP 89301198 A EP89301198 A EP 89301198A EP 89301198 A EP89301198 A EP 89301198A EP 0381878 A1 EP0381878 A1 EP 0381878A1
Authority
EP
European Patent Office
Prior art keywords
packet
echo
bus
network
timer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP89301198A
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English (en)
French (fr)
Other versions
EP0381878B1 (de
Inventor
Roland John Burns
Martyn James Riley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HP Inc
Original Assignee
Hewlett Packard Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hewlett Packard Co filed Critical Hewlett Packard Co
Priority to DE68919674T priority Critical patent/DE68919674T2/de
Priority to EP89301198A priority patent/EP0381878B1/de
Priority to US07/475,694 priority patent/US5226036A/en
Publication of EP0381878A1 publication Critical patent/EP0381878A1/de
Application granted granted Critical
Publication of EP0381878B1 publication Critical patent/EP0381878B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L43/00—Arrangements for monitoring or testing data switching networks
    • H04L43/50—Testing arrangements

Definitions

  • the present invention relates to a network diagnostic tool and relates particularly, but not exclusively, to a diagnostic tool for mapping the position of network nodes on a local area network (LAN).
  • LAN local area network
  • a network diagnostic tool for use in determining the position of a network node along a bus, wherein packets from the network node propagate in both directions along the bus, characterised by means for measuring the time difference between the arrival at predetermined locations of corre­sponding packets which have travelled in opposite direc­tions along the bus.
  • the predetermined locations are at the two ends of the bus.
  • the invention may be embodied by attaching a connection to each end of the LAN and monitoring the time at which a packet arrives at each of the ends. However, in this case a connection is made to each end of the LAN and the delay in the connections themselves must be measured and allowed for in subsequent measurements.
  • a network diagnostic tool for use in determining the position of a network node along a bus wherein packets from the network node propagate in both direc­tions along the bus, characterised by timer means for receiving a packet sent from the network node and propa­gating in one direction along the bus, echo means for receiving the corresponding packet propagating in the opposite direction along the bus and for subsequently sending an echo packet to the timer means and means for calculating the time delay between the arrival of the packet and the echo packet at the timer means.
  • the timer means and echo means comprise means for detecting packet arrival times and for identifying the source address of arriving packets.
  • the echo means preferably comprises means for detecting the transmission time of a packet relative to its arrival time.
  • the timer means and echo means may comprise the same hardware components and may each be embodied on computer card.
  • a method for determining the position of a network node on a communications network comprising a bus to which the network node is connected and timer means and echo means connected at opposed ends of the bus, characterised by the steps of: sending a packet from the network node onto the bus so that the packet propagates in both directions along the bus; receiving the packet propagating in one direction at the timer means; receiving the packet propagating in the opposite direction at the echo means and subsequently sending an echo packet in said one direction; receiving the echo packet at the timer means; determining the time delay between receipt of the packet and the echo packet at the timer means.
  • the method may further comprise sending a packet con­taining echo time information from the echo means to the timer means.
  • the method may comprise initially sending a packet between the timer means and the echo means identifying the network address of the network node.
  • the network diagnostic tool comprises packet detecting means con­nected to a first end of the bus and timer means con­nected to a second end of the bus wherein the timer means is capable of packet detection and means for transmitting a signal from the packet detecting means to the timer means indicating receipt of a packet by the packet detecting means.
  • the timer means is operable to calculate the time difference between the arrival of a packet from the second end of the bus and the arrival of a signal indicating receipt of a packet by the packet detecting means.
  • the timer means comprises first stor­age means for storing the time of arrival of a signal indicative of the receipt of a packet by the packet detecting means and second storage means for storing the time of arrival of a packet from the second end of the bus.
  • the timer means comprises a microprocessor system for utilising the values stored in the first and second storage means to calculate the position of the network node along the bus.
  • Embodiments of the invention will be described with regard to the IEEE 802.3 network by way of example and it should be understood that the invention is also applicable to other types of network.
  • Figure 1 shows a LAN indicated generally at 10 com­prising a shared multi-access bus 12 and several workstations 14, 16, 18, 20 and 22.
  • the workstations 20 and 22 are connected to the ends of the bus 12 and also function as timer and echo stations respectively.
  • the workstation 14 represents the network node whose posi­tion is to be determined and the remaining workstations are shown in dotted lines.
  • the diagnostic tool operates as fol­lows:
  • timer station 20 and echo station 22 Communication between the timer station 20 and echo station 22 is needed in order to synchronise activity eg. as to which is the workstation under investigation. Therefore, a communications protocol is required between the timer and echo stations 20 and 22.
  • Both the timer and echo stations may be computers with special purpose LAN interfaces which also allow the LAN to be used for normal communication.
  • the timer and echo stations 20 and 22 comprise special purpose time consistent matching hardware for identifying packets and for enabling pack­et transmission after a measured delay.
  • the 'time consistent matching hardware' is meant that the time taken to detect the arrival of a packet is the same for both sets of hardware and that the echo time can be measured consistently. Since the packet matching and timing functions are common to the timer and echo sta­tions 20 and 22, a common interface card could be de­signed which performs all the necessary functions of the timer and echo stations.
  • the timer means in the timer station 20 is indicated generally at 30.
  • the timer means 30 comprises a microprocessor system and network controller 32, a transmit time register 34, a receive time register 36, a counter 38 and an oscillator 40.
  • the timer means 30 communicates with the LAN 10 by means of a network transceiver 42, such as a standard IEEE 802.3 transceiver.
  • Incoming signals are supplied from the transceiver 42 to the microprocessor system 32 via a data receive amplifier and filter 44 and a line decoder 46, such as a Manchester decoder.
  • Incoming signals are supplied from the network transceiver 42 to the receive time register 36 via a carrier or packet detect device 48.
  • Signals are supplied from the microprocessor 32 to the network transceiver 42 via a line encoder 50, such as a Manchester encoder, and a transmitter amplifier 52.
  • the echo means in the echo station 22 comprises the same components as the timer means 30. Both the timer means 30 and the echo means may form part of a computer card. It will be understood that the timer means will not make use of the transmit time register 34. The "write" signals to the transmit time and receive time registers 34 and 36 must be generated accurately at the point of packet transmission and reception respectively.
  • timer and echo stations 20 and 22 implement the algorithms described as follows and as illustrated in Figure 3:
  • the system is arranged so that the packet matching functions are carried out without tight time con­straints.
  • the network diagnostic tool may be configured so as to echo all packets received, or all packets received within a selected time period, rather than only to echo packets from the chosen workstation.
  • the timing resolution necessary in the timer means 30 depends upon the speed of propagation on the network and the required accuracy of network node position resolu­tion along the bus.
  • the propagation speed is approximately 0.2 metres per nano­second.
  • the minimum recommended distance between any two stations is 2.5 metres.
  • the counter 38 In order to provide this timing resolution the counter 38 is required to operate at a frequency equal to or greater than 40 megahertz. To provide the necessary accuracy the counter must be accurate to greater than 25 ns over the complete interval timed.
  • the minimum packet length on an IEEE 802.3 network is 596 bits and the transmission rate is 10 Mbits/s.
  • the algorithm requires that a time interval equivalent to the transmission time of a minimum size packet plus upto twice the end to end propagation delay plus the time delay between packet receipt and packet transmission at the echo station be measured.
  • the above embodiment provides a network diagnostic tool for ascertaining the position of a network node along a multi-access bus without the need for any external connections to the network.
  • FIG. 4 shows a LAN 100 comprising a multi-access bus 102 and network nodes 104 and 106. Packets from the network nodes travel in both directions along the multi-access bus 102.
  • a packet detect device 108 is connected to the first end of the bus 102 and a timer device in the form of a special purpose network node 110 is connected to the other end of the bus 102.
  • a cable 112 interconnects the packet detect device 108 and the special purpose network node 110.
  • the network diagnostic tool depicted in Figure 4 operates as follows.
  • T1 time of arrival
  • T2 time of arrival
  • V is the propagation speed on the network.
  • the sign of x indicates with respect to which end of the bus 102 the calculated distance is to be used.
  • the packet detect device 108 comprises a network receiver 114, a packet detector 116 and a signal transmitter 118.
  • the special purpose network node 110 comprises a microprocessor system 120 which receives timing data from two receive time registers 122 and 124.
  • An oscillator 126 provides clock signals to a counter 128 which is connected to the registers 122 and 124.
  • a signal detector 130 detects signals sent from the signal transmitter 118 via the cable 112.
  • a network receiver 132 receives packets from the bus 102 and sends these to a packet detector 134 connected to the register 124 and also to an amplifier and filter 136.
  • the amplifier and filter 136 is connected to a line decoder 138 which supplies signals to the microprocessor system 120.
  • a packet emitted from the network node 104 is received by the network receiver 114 which supplies signals to the packet detector 116 which provides a signal pulse which is amplified by the signal transmitter 118 to produce a signal which indicates the arrival of a pack­et.
  • This signal travels via the cable 112 to the signal detector 130 of the special purpose network node 110 which causes the register 122 to latch the value of the counter 128.
  • the corresponding packet arriving at the second end of the bus 102 is transferred via the network receiver 132 to the packet detector 134 which produces a signal causing the register 124 to latch the value of the counter 128.
  • the amplifier and filter 136 transfer signals from the network receiver 132 to the microprocessor system 120 via the line decoder 138 where the transmitted packet data will be recovered.
  • the microprocessor system 120 identifies the network node source address supplied in the data packet and reads the contents of the registers 122 and 124 after a delay which is longer than the network propagation delay. In effect the microprocessor is alerted to the arrival of a packet at the second end of the bus 102 soon after the packet begins to arrive and then waits for the contents of the registers 122 and 124 to change.
  • V is the propagation speed on the network and t p and t q are as explained above.
  • the sign of the result indicates whether the calculated distance is with re­spect to the first or the second end of the bus 102.
  • the time taken to transmit or receive a packet is much greater than the propagation time along the network. This means that there is no real chance of spurious measurements being made as a result of confu­sion between different packets sent by a single network node.
  • measurement accuracy and reliability may be improved by taking multiple readings and averaging these.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Small-Scale Networks (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
EP89301198A 1989-02-08 1989-02-08 Verfahren und Gerät zur Diagnose von Netzwerken Expired - Lifetime EP0381878B1 (de)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE68919674T DE68919674T2 (de) 1989-02-08 1989-02-08 Verfahren und Gerät zur Diagnose von Netzwerken.
EP89301198A EP0381878B1 (de) 1989-02-08 1989-02-08 Verfahren und Gerät zur Diagnose von Netzwerken
US07/475,694 US5226036A (en) 1989-02-08 1990-02-06 Network diagnostic tool

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP89301198A EP0381878B1 (de) 1989-02-08 1989-02-08 Verfahren und Gerät zur Diagnose von Netzwerken

Publications (2)

Publication Number Publication Date
EP0381878A1 true EP0381878A1 (de) 1990-08-16
EP0381878B1 EP0381878B1 (de) 1994-11-30

Family

ID=8202586

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89301198A Expired - Lifetime EP0381878B1 (de) 1989-02-08 1989-02-08 Verfahren und Gerät zur Diagnose von Netzwerken

Country Status (3)

Country Link
US (1) US5226036A (de)
EP (1) EP0381878B1 (de)
DE (1) DE68919674T2 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0474380A1 (de) * 1990-09-04 1992-03-11 Hewlett-Packard Company Verfahren und Gerät zur Überwachung eines Netzes
EP0474378A1 (de) * 1990-09-04 1992-03-11 Hewlett-Packard Company Verfahren und Gerät zur Kollisionsüberwachung in einem Netz
US5198805A (en) * 1990-09-04 1993-03-30 Hewlett-Packard Company Method and apparatus for monitoring a network and locating a node using signal strength calculations
US6804624B2 (en) 2001-08-31 2004-10-12 International Business Machines Corporation System and method for determining the location of remote devices

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5815344A (en) 1992-02-17 1998-09-29 Sony Corporation Disc cartridge loading apparatus
JP3720364B2 (ja) * 1994-09-12 2005-11-24 日立電子サービス株式会社 Ｌａｎシステムの物理的構成情報を採取する方法、衝突端末の特定方法およびノイズ発生位置検出方法
US5706440A (en) * 1995-08-23 1998-01-06 International Business Machines Corporation Method and system for determining hub topology of an ethernet LAN segment
WO1997027685A2 (en) * 1996-01-29 1997-07-31 Lecroy Corporation Packet network monitoring device
DE19710971A1 (de) * 1997-03-17 1998-09-24 Siemens Ag Verfahren zur Bestimmung der Laufzeit eines Telegramms sowie Teilnehmer zur Durchführung des Verfahrens
KR20040094437A (ko) * 2002-03-12 2004-11-09 코닌클리케 필립스 일렉트로닉스 엔.브이. 두 개의 노드들 사이의 프록시미티를 결정하기 위한타이밍 신호들의 사용
AU2003293164A1 (en) * 2002-11-27 2004-06-23 U-Nav Microelectronics Corporation System and method for networking a plurality of nodes
US8149168B1 (en) * 2006-01-17 2012-04-03 Trueposition, Inc. Position determination using wireless local area network signals and television signals

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US4766549A (en) * 1984-11-30 1988-08-23 Electric Power Research Institute, Inc. Single-ended transmission line fault locator

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0474380A1 (de) * 1990-09-04 1992-03-11 Hewlett-Packard Company Verfahren und Gerät zur Überwachung eines Netzes
EP0474378A1 (de) * 1990-09-04 1992-03-11 Hewlett-Packard Company Verfahren und Gerät zur Kollisionsüberwachung in einem Netz
US5198805A (en) * 1990-09-04 1993-03-30 Hewlett-Packard Company Method and apparatus for monitoring a network and locating a node using signal strength calculations
US6804624B2 (en) 2001-08-31 2004-10-12 International Business Machines Corporation System and method for determining the location of remote devices

Also Published As

Publication number Publication date
DE68919674T2 (de) 1995-04-06
EP0381878B1 (de) 1994-11-30
DE68919674D1 (de) 1995-01-12
US5226036A (en) 1993-07-06

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